Telephone-receiver.



H. R. STUART. TELEPHONE RECEIVER. APPLICATION FILED JUNE 29,-1909.

Patented N0v.22, 1910.

2 SHEETS-SHEET 1.

I i/fneooeo H. R. STUART. TELEPHONE RECEIVER.

APPLICATION FILED JUNE 29, 1909. 976,230. Patented Nov. 22, 191.0

2 SHEETS-SHEET 2.

Wbtueooeo: 8 me ntoz I a "P f a} w 1. mic mamas Mk2 mana e HARVE R. STUART, 0F NEWARK, NEW JERSEY.

TELEPHONE-RECEIVER.

Specification of Letters Patent;

Patented Nov. 22, 1910.

Application filed June 29, 1909. Serial No. 505,013.

{fo all whom it may concern; Be it known that I, HARVE R. STUART, a

citizen of the United States, residing at Newark, in the county of Essex and State of I; New Jersey, have invented certain new and useful Improvements in Telephone-Receivgrs, of which the following 1S a full, clear, and exact description.

This invention relates to telephone receivers, particularly for use in telegraphoncs where only feeble operating currents are available, and where clear sound reproduction is important.

'A type ofreoeiver has hitherto been. proposed making) use of a solenoid coil in place I of a magnet obbin, the solenoid coil acting to vary the intensity of attraction between a pair of juxtaposed magnetic poles, winch are caused to be produced within the interior of the solenoid.

,1. The present invention relates to this gen- [tubes or passages. I-make use of a diaphragm with centrally located sound pas sages extending from both sides of the diaphragm, the diaphragm with its sound pas= sages being eccentric within the circular cas- .ing of the device, and cccentrically connected to the operating magnet or magnets, the latter being contained within the casing on the more spacious side thereof with respect to the eccentric sound passage. I further make use of two operating magnets of the solenoid type, and provide fixed and movable polar extensions which project into the interiors of the respective solenoids. The IBSPCClZlX'B movable polar extensions within the solenoids, are rigidly connected together in my preferred construction and rock in such a manner that. one is entering its solenoid while the other is receding therefrom. This rocking member or armature has an arm from which a wire or connection extends to the diaphragm so as to constitute a multiplying lever. The sound passages being in central alinement with the diaphragm are of course free and undisturbed by the above mentioned wire or connection which is eccentric to the diaphragm and to the sound passages. I also provide a particularly advantageous form of sound chamber acting in con uncy which a more simple and I tion with the sound delivery tubes. W run these various and other objects in View, my invention consists in the features of construction and combination as hereinafter set forth andclaimed. I

In the drawings: Figure l is a side or end view of a telephone receiver embodying the principles of my invention. Fig. 2 is a sectional view on the line IIII of Fig. 1, the electrical connections being omitted. Fig. 3

' is a section on the line III III'of Fig. 1.

Fig. 4 is a View similar to Fig. 1 with part of the casing removed. Fig. 5 is a similar view showing'the diaphragm and additional parts of the casing removed. Fig. 6 is a sectional view through the operating magnets or solenoids.

Referring to the drawings, 1 designates a casing, which I construct with one comparativelyheavy side or plate 2 constitutlng a base for the support of the diaphragm and all the operating arts. The outer face of the plate 2 is cham cred with a generally flat circular depression or cavity 3 which is cocentric to the outline of the plate 2 as clearly shown in Fig. 4. The central portion of the cavity 3 is coned inward to an increased depth merging at the center into an orifice 4 which is continued through into a curved pipe 6.

7 denotes a disk also having an inwardly coned face 8 which merges at the center into a passage 9 communicating with the curved pipe 10. The disk 7 is designed to fit within the cavity 8 where it is secured by screws or similar fastening devices 11.

12 denotes a, diaphragm clamped beneath the disk 7 so as to vibrate in the chamber formed between the base 2 and the disk 7. In this relation the diaphragm sets up air vibrations which travel out through the respective tubes or passages 6 and 10. The location of the diaphragm 12 and its coaxial sound passages eccentric in the casing 1 providcs a more or less spacious cavity on one side of the diaphragm axis and in this cavity I locate the operating solenoid magnets 16.

a passage 5 Two of these are provided with their axes in aplane more or less distant from the'axis of the diaphragm. The solenoids are fixed and supported in this relation by the pole piece 1730f a permanent magnet 18 secured to the base 1 by the bolts 19. The pole piece 17 is preferably forked or furcated so as to evenly distribute the magnetism of this pole of the magnet 18 into the respective solenoids;

ticular ein )odinient of myinvention herein shown. Tlie other. pole 20 of the magneLalso has a pole piecedenoted 21 and which su ports a rigid soft in a stud or post. 22. i T e upper extremity 24 of this stud. is pointed or otherwise formed to constitutethe equiva- 17, soas to be adjusta lent of a knife-edge or pivot.

2G denotes a non-magnetic standard'similar to the iron post 22 but located on the other side of the solenoids 16.

28 denotes an armature having notches or recesses 29 on the'undersides of its ends, into which the u iper extremities of posts '22 and 26 enter. a this way thearnniture'i28 is delicate] Y pivoted to .rock or oscillate in the plane 0 the axes of the solenoids 16. The armature 28 has polar extensions 30 which project into the hollow interiors of the solenoids. f

' 31 denotes corresponding polar extensions i of the pole piece 17, and which project into close proximity to the extensions'30. The latter extensions 31 are made threaded in their engagement with-theprongs of the pole piece le byJa screw river received in their notched exposedends 33 in an obvious manner.

3'4 denotes lock nuts on the threaded en$ of the' polai' extremities 3f to secure them in their adjusted relation. j At. a. convenient point of the armature ,28 I provide a light rigid arm 35 proj'eetin into close proximity to the 'wall 01 the soun p'assage At this oiiit the arm has a wire connection 36 wit thejdiaphragni 12, this wire passing through a minute perforation 37 at the base'of the sound assagc. 5. "This perforation is so small as to liave n0 substantial efi'ect from an acoustic standpoint, the sound chamber acting in substantially the ame way on this side of the diaphragm as on the other, where of course there is no corresponding perforation or connection whatever; the wire 36 in fact substantially lillin g the aperture or perforation.

The casing lis supported in place. and'the magnet 18 with itsassoeiated )arts is given additional support by a supplemental base or plate 38 which is-fixed to the base 2 by the bolts 19, and an additional. postor strut40.

39 denotes a sheet metal shell secured to the plate 3S and havin a flanged edge enibracing a cylindrical s ell 41 which covers 1 the interior parts.

43 denotes a block projecting through the wall' ll and having terminal screws 44 for the electrical connections.

45 denotes clips within the'casing and joined 'to the terminals 4}, and from which the connections may be made to the SOlOllOit s 16, which are conneeted'in series or multiple circuitfin an ordinary manner, the windings however heing in opposite directions.

The sound tubes 6 and 10 are convenientlv connected to the tubes 6 and 10 and lead to ordinary ear pieces which it is .not necessary to show.- 1 e The use and operation is as follows: Assuming that the terminals-44- are connected in the circuit of a telcgraphone or receive voice currents from any other source. it is evident that. pulsationswill be produced in their magnetizing force. A magnetic held or flux traverses'the interiors of both so l'enoids in the same direction oii account of thc respect-ive polar extensions 30 and ill from the-two poles of the permanent magnet 18. inasmuch as the solenoids are wound in opposite directions. this field through one is HSSlStQtlflYllllt-l the field through the other is opposed, and vice versa, by any change of current whatever in the operating circuit, The resultant changes in the field or flux of the solenoids produce corresponding variations in the attraction between the polar extensions 30,ll 1 if the respective solenoids, so that the artrlature 28 rocks tin its ivots continuously under the changing lorces.

This movementis directly communicated through the arm to the diaphragm 12' so that the diaphragm vibrates in its sound chamber. The diaphragm may be made of light and flexible material; and the magnetic system may be made fairly heavv Hill- '1 A? reable to its magnetic requirements. salt is that substantially all the energy of u air vibrations.

- have: men inadc to utilize l lh ide of the same vibrating diaphragm. hut in which the. chamber at one side was greatly dill'crciit in fotln and capacity from that f the other side. I

1! my invention not only are the chainbers of l otlrsidcidentical. but each may be inadca small in c'aparirv a (lt ll '(tl. and

of exactly the best theoretical form for sound reprmlnction. l have chosen the liaring outline shown which gives the best practical results. The essential feature of the-formation lies in the fact that the flaring cone of thesound chamber pre ents a 1 125 rervacul'e outline with the plane of the diaphragm at all points or element 'rounding into the sound tube at the middle and merging into the plane'of the dia 'ihragin at the circumference. e

I make the angle of the flaring cone of the current fluctuations is"utili'zed in setting It will be pai'ticulaigly "0 served that the movement of the .dnt-

iro

the sound chambers-of such an inclination that the height thereof at the middle, or in other words the separation of the edge or entrance of the passage 5 from the diaphragm, is one-fourth the diameter of the sound passage 5. This value is derived from the principle that the soundchambers should have as small capacity as possible, but the capacity should not be small enough to restrict the sound passage at any point to a less area than thearea of the tube 5. Substantially all the sound assing from the circumference or body 0 the diaphra m toward the center has to traverse an annu ar space at the entrance to the sound passage 5 which is in the form of a'small cylinder having the area wDIi;-1rD being the circumference and H the height of the small cylinder mentioned.- The area of the sound 1:1) passage 5 1s, of course,

. 4 and equating thetwo areas gives the result H=% which .is the result above mentioned.

What I claim, is l. A telephone receiver comprising a generally cylindrical casing having an eccentric diaphragm, a pair of solenoids Within said erally cylindrical casing having an eccentric diaphragm, a pair of solenoids Within said casing, an armature having a grooved por-' tion and having polar extensions projecting into said solenoids, an iron post received in the grooved portion of said armature, a

permanent magnet joined to said post and having polar extensions also projecting into said solenoids, and a connection from said armature to said diaphragm, said connection extending in a direction along its path of movement when the armature vibrates.

3. A telephone receiver comprising a pair of solenoids, an armature having polar extensions projecting into said solenoids and pivoted to tilt on an axis therebetween, a diaphragm, similarly shaped sound chambers on either side of said diaphragm, and a Wire extending from said armature to said diaphragm through a hole in one of said chambers and in a direction along its path of movement when the armature vibrates.

4. In a telephone receiver, a substantially circular magnet having one bifurcated pole piece, polar extensions thereon, solenoids into which sa d extensions pro ect, a movable armature also having polar extensions projecting into the solenoid, and a d1a phragm connected to said armature.

5. In a telephone receiver, a substantially circular magnet having one bifurcated pole piece, polar extensions thereon, solenoids into which said extensions project, an armature also having polar extensions projecting into the solenoid, a diaphragm connected to said armature, and means for adjusting the polar extensions of said magnet in said solenoids.

6. In a telephone receiver, a sound chamber of shallow conical outline terminatin in a cylindrical sound passage at its centre portion, said conical outline having a height at its middle ortion equal to one-quarter the diameter 0% said sound passage.

7. A telephone receiver comprising a pair of solenoids, an armature pivoted to tilt on an axis therebetween, a diaphragm, a sound chamber onone side of said dia hragm, and a member extending from sai diaphragm through a hole in the side of said chamber, substantially in a direction along its path of movement When the armature vibrates.

8. A telephone receiver comprising a casing having a diaphragm, a pair of solenoids within said casing,.an armature havin a grooved portion and having olar extenslons projecting into said s lenoi s, an iron post received 1n said grooved portion of the armature, a magnet joined to said post and a connection from said armature to said diaphragm.

9. A telephone receiver comprising a casing having a diaphragm, a pair of solenoids Within said casing, an armature having a grooved portion and having olar extensions projecting into said solenoi s, an iron post received inv said grooved portion of the armature, a magnet joined to said 0st, a connection from said armature to said diaphragm, said connection extending in a direction along its path of movement when the armature vibrates.

in a cylindrical sound-receiving passage at. ts central portion, sald conical outline having a height at its middle portion materially less than the diameter of said sound passage.

12. In a telephone receiver, an arcuate magnet having one bifurcated pole piece, polar extensions thereon, solenoids into which said extensions project, an armature" of-said polc-piece, an armature, a diaphragm cooperating with said extensions, and :1 diaphragm connected to said armature.

'13. In a telephone receiver, an arouate magnet having a furcated pole piece, solenoids disposed adjacent the respective prongs of said pole piece, an armatnre, and a diaphragin co'nnected'to said armature.

14. In a telephone receiver, an arcuate magnet having a, furcatcd pole piece, solenoids disposed adjacent the respective prongs connected to said armature, and magnetic parts disposed in the interior of said sole noids to provide air gaps between the respective extremities of each of said solenoids.

In witness whereof, I subscribe my signature, in the presence of two witnesses.

' HARVE R. STUART. "Vitnesses:

VALDO M. CHArIN, WILLIAM C. LARY. 

